1. Technology Field
The present invention generally relates to a data writing method, and more particularly, to a data writing method for writing data into a multi-level cell (MLC) NAND flash memory and a storage system and a controller using the same.
2. Description of Related Art
Along with the widespread of digital cameras, camera phones, and MP3 in recently years, the consumers' demand to storage media has increased drastically too. Flash memory is one of the most adaptable memories for such battery-powered portable products due to its characteristics such as data non-volatility, low power consumption, small volume, and non-mechanical structure. Besides being applied in foregoing portable products, flash memory is also broadly applied to external products such as flash memory cards and flash drives. Thereby, flash memory has become one of the most focused electronic products in recent years.
The development of flash memory has been going from single level cell (SLC) NAND flash memory towards multi-level cell (MLC) NAND flash memory. Due to the physical characteristics of MLC NAND flash memory, the voltage is not very stable when some page addresses thereof are programmed and which may further affect the adjoining page addresses. Accordingly, even though a MLC NAND flash memory can provide larger storage capacity, the storage reliability thereof is not very satisfactory. In other words, the data written by a previous writing command may be damaged when a programming error occurs to a page address written by a current writing command. Besides, the storage capacity of MLC NAND flash memory has been increased constantly so as to be used as hard disk (for example, a solid state drive (SSD)). Thus, data reliability has become one of the most important factors for the success of SSD which uses MLC NAND flash memory as its storage medium.
Accordingly, to resolve the aforementioned problem, a data writing method which can improve the data reliability of MLC NAND flash memory is needed.